Green preparation of carbon dots by Jinhua bergamot for sensitive and selective fluorescent detection of Hg2+ and Fe3

An environmental-friendly and low-cost hydrothermal method was developed for synthesis of water-soluble fluorescent C-dots with Jinhua bergamot as a carbon source. The fluorescence of the C-dots can be served as a fluorescent probe for the detection of Hg2+ or Fe3+ with high sensitivity and selectivity, respectively. •A green and low-cost hydrothermal method was developed for synthesis of water-soluble fluorescent C-dots.•Jinhua bergamot was used as a carbon source.•The as-prepared C-dots displayed a bright blue fluorescence and high quantum yield of 50.78%.•The C-dots were explored for fluorescent detection of Hg2+ and Fe3+ with high sensitivity and selectivity. Green, low-cost, and water-soluble fluorescent carbon dots were prepared under hydrothermal conditions, with a plant of Jinhua bergamot as a carbon source. The as-synthesized C-dots have better stability and relatively high photoluminescence with a quantum yield of 50.78%, along with the fluorescence lifetime of ca. 3.84ns. Their photoluminescence can be significantly quenched by simply using the buffer solution of HAC–NaAC for Hg2+ and Tris–HCl for Fe3+. Based on this, we explored for selective detection of Hg2+ and Fe3+ with high selectivity, fast response, low cost, and broad linear ranges of 0.01–100μM for Hg2+ and 0.025–100μM for Fe3+, as well as low detection limits of 5.5nM (Hg2+) and 0.075μM (Fe3+) (S/N=3).